page_title: Yogo sapphire
section_title: Early mining
hierarchical_section_title: Yogo sapphire / History / Early mining
caption_attribution_description: Sapphire mine of Yogo District, Montana. Face of dike in open cuttings.
context_page_description: Yogo sapphires or Montana sapphires are blue sapphires, a colored variety of corundum, found in Montana, primarily in Yogo Gulch in Judith Basin County, Montana. Yogo sapphires are typically cornflower blue, a result of trace amounts of iron and titanium. They have high uniform clarity and maintain their brilliance under artificial light. Because Yogo sapphires occur within a vertically dipping resistive igneous dike, mining efforts have been sporadic and rarely profitable. It is estimated that at least 28 million carats of Yogo sapphires are still in the ground. Jewelry containing Yogo sapphires was given to First Ladies Florence Harding and Bess Truman; in addition, many gems were sold in Europe, though promoters' claims that Yogo sapphires are in the crown jewels of England or the engagement ring of Princess Diana are dubious. Today, several Yogo sapphires are part of the Smithsonian Institution's gem collection.
  Yogo sapphires were not initially recognized or valued. Gold was discovered at Yogo Creek in 1866, and though "blue pebbles" were noticed alongside gold in the stream alluvium by 1878, it was not until 1894 that the "blue pebbles" were recognized as sapphires.
context_section_description: Yogo sapphires were ultimately traced from the alluvium to their source. In February 1896, a sheepherder named Jim Ettien found the sapphire mother lode: the Yogo dike.  Ettien was prospecting for gold, and found sapphires after washing gravel he found in a fissure within a limestone outcrop. Ettien staked two claims. The vein turned out to be 5 miles (8 km) long and several other miners promptly staked claims along it. Ettien sold his claims to Hoover; Hoover in turn sold his interest in eight original mining stakes, known as the "New Mine Sapphire Syndicate", to his two partners for $5,000 (approximately $150,000 as of 2020). This site was 5 miles (8 km) from Yogo City. In 1899, Johnson, Walker and Tolhurst, Ltd. of London purchased the New Mine Sapphire Syndicate for $100,000 (approximately $3.1 million as of 2020). At that point, the operation became unofficially known as the "English Mine".
  On July 4, 1896, two other Americans, John Burke and Pat Sweeney, staked six mining claims on the western portion of the Yogo dike—areas Hoover had deemed unfit for mining. These claims were collectively known as the "Fourth of July Claim", and became known as the "American Mine". In 1904, the mine was bought by the American Gem Syndicate, and it sold in 1907 to the American Sapphire Company.
  One of the Englishmen who came to the area was Charles Gadsden of Berkhamsted, Hertfordshire. By 1902, Gadsden was promoted to resident supervisor of the English Mine, and he quickly turned its focus from gold to sapphires. Gadsden's security measures were very tight, as weight-for-weight, rough sapphires were and continue to be  worth much more than gold. The English Mine flourished until the 1920s, but floods on July 26, 1923, so severely damaged the mines that they never fully recovered. Between the aftermath of flooding and hard economic times, the English Mine finally failed in 1929. It had recovered more than 16 million carats (3.2 t) of rough sapphires that produced 2.5 million carats (500 kg) of finished gems valued at $25 million in 1929 dollars (approximately $370 million as of 2020). A series of other firms mined sapphires there, but with marginal success. For much of the 1930s and 1940s Gadsden worked the mine alone and used his own money to pay its property taxes.  He remained caretaker of the mines until shortly before his death on March 11, 1954.
  The American Mine operations were less profitable than those of the English Mine. While the English Mine used superior mining and management techniques on a richer lode, the American Mine suffered from insufficient space and lack of water for ore weathering. Roughs from the English Mine were shipped to London and sold in Europe, often with claims they were sapphires from the Far East, while the American Mine had difficulty marketing its gems within the United States. The American Sapphire Company, which used local gemcutters from Great Falls, went bankrupt in 1909; a new firm, the Yogo American Sapphire Company, bought the American Mine, but was bankrupt by 1913. Gadsden and his wife had convinced the New Mine Sapphire Syndicate to buy out the Yogo American Sapphire Company in 1914, and in doing so, the English syndicate gained control of all known Yogo deposits.  They quickly recouped the purchase price by washing the tailings left behind by previous operators of the American Mine.
caption: Face of the Yogo dike in open cuttings in 1897
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